| Lufengosaurus | |
|---|---|
 | |
| Holotype ofL. huenei on display at thePaleozoological Museum of China. | |
Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Reptilia |
| Clade: | Dinosauria |
| Clade: | Saurischia |
| Clade: | †Sauropodomorpha |
| Family: | †Massospondylidae |
| Genus: | †Lufengosaurus Young, 1940 |
| Species | |
| Synonyms | |
| |
Lufengosaurus (Chinese:祿豐龍 or 禄丰龙, meaning "Lufeng lizard") is agenus ofmassospondyliddinosaur which lived during the EarlyJurassic period in what is now southwesternChina.[1]
The first remains ofLufengosaurus were found during the late 1930s bygeologistBien Meinian in theLower Lufeng Formation at Shawan, nearLufeng in theYunnan Province of China. From 1938 onwards, Meinian was joined by paleontologistC. C. Young (Chinese: 杨钟健, Yáng Zhōngjiàn). Young would go on to name the animal'stype species,Lufengosaurus huenei, in 1940, with the generic name referring to Lufeng where it was found and the specific name honoring Young's old tutor, the German paleontologistFriedrich von Huene.[2] Young would go on to publish a detailed description of the animal the following year and would assign specimenIVPP V15 as theholotype of the species, this specimen consisting of a nearly completeskeleton with a well-preservedskull.[3]
A second species ofLufengosaurus,L. magnus, was also named by Young in 1940 in the same paper asLufengosaurus huenei and would be fully described by him in 1947. As its specific name suggests, with the word magnus meaning "the large one" inLatin, this species was considered separate fromL. huenei due to its significantly larger size, with it being up to a third larger thanL. huenei in length. However, most authors have regarded it as ajunior synonym ofL. huenei, with its specimens being said to simply represent larger individuals of the type species.[4]
Another "prosauropod" Young named in 1940,Gyposaurus sinensis, was noted by him to be distinct fromLufengosaurus on behalf of the limbs being at least 50% smaller, though similarities in overall form were noted.[2] This genus has subsequently been referred toLufengosaurus on two separate occasions: once byPeter Galton in 1976 and once in a 2017SVP presentation by Wang and colleagues.[5][6] The referral is however doubted by some.
Lufengosaurus would be referred to another genus yet again in the 1980s, withMichael Cooper suggesting thatLufengosaurus andYunnanosaurus were species of theSouth African genusMassospondylus 1981.[7] However, a reanalysis in 2005 byPaul Barrett and colleagues, performed on the skull ofLufengosaurus huenei established it firmly as a valid genus separate from bothMassospondylus andYunnanosaurus based on craniodental characteristics.[4] This same 2005 study would provide an extensive and detailed redescription of the cranial osteology of the holotype skull of the animal.
The year 1985 sawZhao Xijin name a new species of the animal in a list of Jurassic reptiles from China. Zhao named itLufengosaurus "changduensis", with the naming of the animal being prompted by the recovery of a specimen fromTibet.[8] The species has however remained undescribed and thus anomen nudum, with neither the reported Tibetan specimen nor any other material being formally assigned to it after it was named.
In 2015, preservedcollagenprotein was found in aLufengosaurus fossil by an international team led byYao-Chang Lee ofTaiwan'sNational Synchrotron Radiation Research Center. The protein, described inNature Communications (2017 January 31), was over 100 million years older than any previously recorded fossil protein, having sizeable implications for our understanding of protein preservation.[9]
Lufengosaurus is often described as a rather small earlysauropodomorph, about 6 metres (20 ft) long.[1] However, when theL. magnus specimens are included, its size is more considerable:Gregory S. Paul estimated a length of 9 metres (30 ft) and a weight of 1.7 metric tons (1.9 short tons) in 2010, while Bensonet al. (2014) estimated a mass of 2.3 tonnes (2.5 short tons).[10][11] For an early sauropodomorph, its neck is rather long and the forelimbs are relatively short. From these it was inferred that the species was bipedal, even before it became common to assume this for all basal sauropodomorphs. Yang published a full osteology ofLufengosaurus in 1941,[3] but was severely hampered in his diagnosis by the war conditions, preventing a full access to literature and making an adequate comparison with related forms impossible. Of the skull a modern description exists. The skull of the holotype is 25 centimetres (9.8 in) long.[4]
Lufengosaurus snout was deep and broad, and it had distinctive bony bumps just behind its largenostrils and on itscheeks. A bony ridge on the side of itsupper jaw might have helped anchorsoft tissue. If so, thenLufengosaurus must have had larger cheeks than most othersauropodomorphs. Its closely spaced, serrated teeth suited a diet of leaves.[12]
About thirty major specimens have been discovered, including those of juveniles.[13] In 1958 a specimen ofLufengosaurus was the first complete dinosaur skeleton mounted in China; a commemorative postage stamp[1] of 8 yuan was issued on 15 April 1958 to celebrate the event, the first time ever a dinosaur was depicted on a stamp.[1] The skeleton is now on display in thePaleozoological Museum of China inBeijing.
Young originally assignedLufengosaurus to the Plateosauridae of the suborder Prosauropoda, noting that it stood close toPlateosaurus fraasianus. It is still sometimes considered a member of Plateosauridae, though some cladistic analyses have found it to be a member of Massospondylidae instead. This matches with our current knowledge ofLufengosaurus' anatomy, which has proven to be more similar to taxa likeColoradisaurus andMassospondylus than was previously thought, withLufengosaurus formerly being considered to have more anatomical similarities withPlateosaurus.[12]Lufengosaurus has historically had a maximum of three named species, only one of these being almost unilaterally considered valid nowadays:L. huenei. The other two species,L. magnus andL. "changduensis", are respectively considered a junior synonym and anomen nudum.[4] Specimens assigned toL. magnus in the past are now referred to the type species instead.
Barret, Upchurch and Wang recoveredLufengosaurus as being the sister taxon toGyposaurus sinensis in their 2005 cladistic analysis.[4] A differing result was recovered from a cladistic analysis done by Fernando E. Novas and colleagues in 2011, which recovered the animal as the sister taxon toGlacialisaurus hammeri.[14] This result was replicated by Oliver W. M. Rauhut and colleagues' 2020 analysis.[15] A simplified version of the resulting cladogram, not showing the part including the Sauropodiform taxa, is shown below.
Like all early sauropodomorphs,Lufengosaurus had much longer hindlimbs than forelimbs and was probably bipedal. It was herbivorous, although it had sharp claws (with an especially large thumb claw) and teeth.[1] These features have been used to support claims, the most recent by Cooper in 1981, thatLufengosaurus may have been at least partially omnivorous,[1] but the sharp teeth witnessed inLufengosaurus and other early sauropodomorphs are similar to those seen iniguanaianlizards – which are herbivorous.[4] Alternatively, the claws may have been used for defense or raking foliage from trees.[1] Embryos of this genus also represent the earliest evidence of vertebrate soft tissue preservation.[16]Lufengosaurus likely engaged in parental feeding as a fullyaltricial animal, given that the bone development in its femora is closer to that of altricial pigeons than precocious chickens.[17]
While originally considered to be a Triassic locality, nowadays the Lufeng Formation is dated to the Lower Jurassic instead (Hettangian-Sinemurian), implying thatLufengosaurus existed in a more recent timeframe than previously thought.
